2015 Mastercraft 5.7

[Oldutskier]

Does anybody know what the source is for the volt reading on the touchscreen (see pic) gauge for the Mastercraft? My pro star is dead in the water. And I can’t figure out which wire is responsible for the reading on the dash. If I can find the wire I think I can identify my problem.

[LoopSki]

Im sure you have but just in case. Have you turned the perko on and off and on ?

[Mastercrafter]

@jpwhit will know better but I’m quite certain that pulls info over the CAN network form the engine ECU. Poke around your starter / ECU / breaker on the engine, and check your engine mounded fuse box.

What happens when you press start.. nothing?

[Oldutskier]

When I turn the key on, don’t hear any of the relays that you normally hear. When I press the start button nothing happens. I’ve had this problem off and on for the better part of three years. It’s always been somewhat manageable until now.

Historically Icould jiggle the bus/relays in the back of the motor and it would fix itself. Earlier this year, I replaced all the relays because I thought they were going bad.

Now, I can’t get it to turn over/start.

[skimtb]

The zero hours would also be concerning. Something seems wrong w computer in my mind. Maybe that is not giving it the go ahead to try and start?

[jpwhit]

The voltage reading is most likely either coming from the PDM or from the Engine ECM. Both provide a CANbus commands to read the system voltage, but I don't know which one the Murphy screen is actually using. There isn't a wire somewhere specifically for the battery voltage. But as @skimtb points out, you aren't getting your engine hours. And that I know for certainty is read from the engine ECM. So, the CANbus communications from the Murphy screen to the engine ECM is not working.

Given the other symptoms you describe, it sounds like you most likely aren't getting power to the Engine wiring harness and therefore the ECM isn't powered up. The first place I'd be checking is the main power ground on the engine. That's a common place to have the kind of intermittent issue you describe if it's not tight. I happen to be at the lake house today, so I'll go take a few pictures of the places to check on my ProStar.

Do you have a handheld volt meter?

[Oldutskier]

So after poking around with a voltmeter, I found that I was only getting 2 to 3 V from the “clean power“ lead. Once I provided a 12 V jumper to the hot side of the clean power fuse at the back of the engine, I would get a voltage reading and the engine hours displayed on the screen.

Now it cranks very strongly but will not fire. I have fuel pressure on the fuel rails. It must me ignition related. No codes are present.

I got up under the dash to try to locate where the “clean power” wire runs from the master switch to the engine, but I was unable to locate it. A wiring schematic would be nice.

[Mastercrafter]

email me.. mikedwagner@gmail.com -- I'll reply with some schematics :)

The 12v clean power lead supposedly pulls power right near the master Perko switch. It may not even make it up to the helm.

Where are you located? I can loan/ship you my laptop/diacom to diagnose non-start if needed.

[jpwhit]

Do you 12V on terminal B on the main engine harness plug? It should be a red wire and that powers the ignition system. Not to be confused with the red wire on terminal A that powers the ECU.

[jpwhit]

You should also have 12V on main engine harness G wire which is purple. If you don't have power there, it could be a bad ignition switch, failed 20A ignition breaker or failed kill switch.

[Oldutskier]

Could never figure out why we lost 12v clean power. Just wired it to the starter. The No Run issue turned out to be the ignition control module.

[Oldutskier]

Could never figure out why we lost 12v clean power. Just wired it to the starter. The No Run issue turned out to be the ignition control module.